OBD-II Code P0547 — What It Means & How to Fix It

What Does This Error Mean?

P0547 means the PCM detected a fault in the exhaust gas temperature sensor circuit for bank 1, sensor 2. This is the downstream EGT sensor — positioned after the first sensor and typically after the diesel particulate filter or catalytic converter. Sensor 2 helps the PCM verify exhaust temperatures after key emissions components. A fault here can disrupt DPF regeneration management and exhaust after-treatment monitoring.

Affected Models

2007 and newer diesel trucks with DPF systems — Ford F-250/F-350 6.7L, Ram 2500/3500 6.7L Cummins, Chevy/GMC 6.6L Duramax
European diesel passenger cars and SUVs — BMW 3/5 series diesel, Volkswagen Passat TDI, Audi A4/A6 TDI
Diesel vans and commercial vehicles with exhaust after-treatment systems
Gasoline vehicles with dual EGT monitoring for turbocharged engine protection
Vehicles with selective catalytic reduction (SCR/DEF) systems requiring downstream temperature monitoring

Common Causes

EGT sensor 2 has failed — internal element damage from repeated heat cycling during DPF regeneration events
Heat-damaged wiring harness on the sensor signal wire — insulation melted or cracked near the DPF
Corroded or loose connector at sensor 2 caused by moisture entering the connector boot
Open circuit in the wiring between sensor 2 and the PCM from a broken wire or bad splice
Short to ground in the sensor 2 signal wire where the harness runs near the DPF body

How to Fix It

Use a scan tool to pull live EGT sensor data. Compare the bank 1 sensor 2 reading to sensor 1. At idle, sensor 2 should read lower than sensor 1 since it sits downstream. Wildly different or flat-line readings confirm a circuit fault.

If sensor 2 reads the same as sensor 1 at all times, it may be stuck or has an open circuit rather than a true temperature reading.
Locate EGT sensor 2 on bank 1. On most diesel trucks it is mounted in the exhaust pipe downstream of the DPF, under the vehicle. The location varies by make — consult your service manual or a model-specific forum for the exact position.

Raise the vehicle safely on jack stands or a lift for access. Never work under a vehicle supported only by a floor jack.
Inspect the sensor connector and surrounding wiring for heat damage. The area near the DPF reaches very high temperatures during regeneration events. Look for melted wire insulation, cracked connectors, and heat-shrink that has slipped off.

Replace any heat-damaged wiring with high-temperature rated wire and connectors designed for exhaust applications.
Disconnect the sensor and perform a resistance test. Measure across the sensor element terminals. Compare the reading to sensor 1 on the same bank — the values should be similar at the same temperature. An open reading indicates sensor failure.

If the sensor reads correctly on the bench but erratically on the vehicle, the harness likely has an intermittent fault.
Replace the sensor if it fails the resistance test. Spray penetrating lubricant well in advance. Use a proper EGT sensor socket to avoid rounding off the sensor body. Torque to specification and apply anti-seize to the threads of the new sensor.

Verify the replacement sensor matches the original — sensor 2 may have a different temperature range or connector than sensor 1.

When to Call a Professional

On diesel trucks, bank 1 sensor 2 is often located in a tight spot under the vehicle near the DPF. Access can require a lift and specialized tools. A shop with diesel expertise can diagnose and replace this sensor for $200 to $500 including labor.

Frequently Asked Questions

What is the difference between EGT sensor 1 and sensor 2?

EGT sensor 1 is the upstream sensor — it measures exhaust temperature entering a component like the DPF or catalytic converter. EGT sensor 2 is the downstream sensor — it measures temperature after that component. The PCM compares both readings to verify that the DPF or converter is functioning correctly.

Will P0547 cause my DPF light to come on?

Often yes — especially on diesel trucks. The PCM uses downstream EGT data to monitor DPF loading and manage regeneration cycles. With an invalid sensor 2 reading, the PCM may disable active regeneration or trigger a DPF fault separately.

How often do EGT sensors need replacement?

On diesel trucks that do frequent DPF regenerations — such as those used for towing or driven mostly in city traffic — EGT sensors typically last 80,000 to 120,000 miles. Highway-driven vehicles with less frequent regeneration cycles can see longer sensor life.